Myocarditis and pericarditis are inflammatory conditions of the heart muscle and sac surrounding the heart respectively. Myocarditis has many causes including viral infections, drugs, and connective tissue diseases. It can cause chest pain, heart failure, and arrhythmias. On biopsy, lymphocytic infiltrate is often seen. Pericarditis can be acute and self-limiting due to viruses, or chronic with fibrosis in conditions like tuberculosis which can lead to constrictive pericarditis. Both conditions require diagnosis via biopsy or imaging and treatment of the underlying cause.

1. MYOCARDITIS
BY
Dr. Mahadev Harani
MBBS, M.Phil, FCPS.
Professor Pathology,
LUMHS Jamshoro.

2. Diverse group of pathologic entities in
which microorganisms and/or an
inflammatory process cause myocardial
injury.

3. ETIOLOGY
• Viral
• Non-viral, Trypanosoma, Trichinosis,
Toxoplasmosis, Diphtheria.
• Non-Infectious due to Hypersensitivity
reactions.
• Drugs.Antibiotics, Diuretics and anti
Hypertensive. Also associated with systemic
diseases of immune origin. RF, SLE,
polymyositis. Cardiac sarcoidosis and
rejection of transplanted heart.

4. MORPHOLOGY
Acute phase heart may be normal or
dilated. Some hypertrophy may be present.
In advance stages of disease ventricular
myocardium is flabby and often mottled
with minute hemorrhagic lesions.Mural
thrombi in any chamber.
During active disease myocarditis is mostly
associated with interstitial inflammatory
infiltrate associated with focal myocyte
necrosis.

5. Continued
Lymphocytic infiltrate is most common and
Endomyocardial biopsy is diagnostic.
Lymphocytic myocarditis is most common.
If the patient survives the acute phase of
myocarditis, the inflammatory lesions either
resolve, leaving no residual changes, or heal by
progressive fibrosis.
Hypersensitivity myocarditis has interstitial
infiltrate principally perivascular, composed of
lymphocytes, macrophages and eosinophils.

6. Giant-cell myocarditis. characterized by
widespread inflammatory cellular infiltrates
containing multinucleate giant cells (formed
by macrophage fusion) interspersed with
lymphocytes, eosinophils, and plasma cells.
Myocarditis of chagas disease show
parasite trypanosomes accompanied by an
inflammatory infiltrate of neutrophils,
lymphocytes, macrophages, and occasional
eosinophils

7. CLINICAL FEATURES
Asymptomatic, recover completely.
Symptomatic, heart failure, arrhythmias
and sudden death.
Symptoms of fatigue, dyspnea, palpitation,
precordial discomfort and fever.
c/f mimic acute MI.
Occasionaly dilated cardiomyopathy is
late complication.

8. Other causes of myocardial disease
Cytotoxic drugs.
Catecholamines, Amyloidosis, Iron over
load, Hyper and hypothyroidism.

9. PERICARDIAL DISEASE
Diseases of the pericardium include
inflammatory conditions and effusions.
Isolated pericardial disease is unusual, and
pericardial lesions are almost always
associated with disease in other portions of
the heart or surrounding structures, or are
secondary to a systemic disorder.
1)Fluidaccumulation 2)Inflammation
3)Fibrous constriction.
Normally fluid 30-50ml thin, clear, strans
colomned fluid.

10. Serous fluid :Pericardial effusion
Blood :Hemopericardium
Pus :Purulent Pericarditis
500ml, chronic globular enlargement.
In acute state 200-300ml produce
compression due to ruptured MI or
aortic dissection

11. PERICARDITIS
Inflammation of pericardium.
Primary Rare, viral in origin.
Secondary Due to cardiac diseases,
thoracic, systemic, metastases, surgical
procedures.

12. Causes.
INFECTIVE:
Virus, pyogenic bacteria, TB, Fungi,
Parasites.
IMMUNOLOGICALLY MEDICATED:
RF, SLE, Scleroderma, Drug
hypersensitivity
reaction
MISCELLANOUS:
MI, uremia, Neoplasia, Trauma, Radiation

13. ACUTE PERICARDITIS
Serous Pericarditis: Produced by non-
infectious inflammatory disease such as RF,
SLE, Scleroderma, tumor, uraemia.
Bacterial pleuritis may cause sufficient
irritation of pericardium.
Viral Infection antedates pericarditis.
MORPHOLOGY: Inflammatory reaction
with few neutrophils,lymphocytes and
histiocytes.

14. Volume of fluid between 50-200
ml,accumulates slowly.
Organization into fibrous rarelr occurs.

15. FIBRINOUS AND SEROFIBRINOUS PERICARDITIS
Serous Fluid mixed with fibrinous exudate.
Common Causes: Acute MI, Dressler
syndrome, Uraemia, Chest radiation, RF,
SLE, Trauma.
IN FIBRINOUS PERICARDITIS
The surface is dry with fine granular
roughening.

16. In sero-fibrinous carditis
Intense inflammatory process, produces
large amount of yellow to brown fluid
with presence of leukocytes and red cells
with fibrin.
Clinically precardial friction rub heard.
Pain, febrile reaction with signs of cardiac
failure.

17. Purulent or suppurative Pericarditis
Invasion of pericardial space by microbes.
a) Direct extension from empyema
b) Seeding from blood
c) Lymphatic extension
d) Direct extension during cardiotomy
Immunosupression pre-disposes to
infection.

18. Continued
Exudate ranges from thin cloudy fluid to
pus 400-500ml, in volume.
Serosal surface red, granular and coated
with exudate.
Microscopically acute inflammatory
reaction seen.
Scarring produce constrictive
pericarditis.
Signs of systemic infection noticed.

19. Haemorrhagic Pericarditis
Blood mixed with fibrinous or suppurative
effusion due to neoplasm. Cytological
examination needed.
Also seen in bacterial infection due to
bleeding diathesis.
Also due to cardiac surgery.

20. Caseous Pericarditis
Rare,due to tuberculosis until proved
other wise.
It leads to chronic constrictive
pericarditis

21. U
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